Stents are tubular devices designed to maintain the patency of a bodily vessel. Stents have been used in a number of different parts of the body including the vasculature, the urinary system, the biliary ducts and the esophagus. A stent is typically delivered to a desired bodily location via a stent delivery system such as a catheter. The stent, disposed about the distal end of the catheter, is inserted in a bodily vessel and delivered to the desired bodily location where it is then deployed.
Stents may be self-expanding, mechanically expandable or hybrids. Examples of self-expanding stents include coil stents and stents made from shape memory materials such as nitinol. One such stent is disclosed in copending, commonly assigned U.S. application Ser. No. 08/511076. Mechanically expandable stents are most often expanded by medical balloons. Such stents are typically made of metals such as stainless steel. An example of the latter is disclosed in U.S. Pat. No. 6,033,433. Hybrid stents may be mechanically expandable in part and self-expanding in part. An example of such a stent is disclosed in copending, commonly assigned U.S. application Ser. No. 09/087526.
In delivering stents, it is important to prevent slippage of the stent on the catheter. A number of techniques to prevent slippage have been disclosed. Copending, commonly assigned U.S. application Ser. No. 09/283375 discloses the use of a balloon with protrusions thereon to grip a stent. The use of securement hubs and other stent securement means disposed about the catheter inner tube is disclosed in U.S. Pat. No. 6,096,056, U.S. Pat. No. 6,007,543, U.S. Pat. No. 5,968,069, U.S. Pat. No. 5,944,726 and U.S. Pat. No. 5,653,691. The use of securement hubs is complicated, however, because when the stent is crimped to the balloon, the force applied to the securement hubs may cause the inner tube to collapse inward. This, turn, may impair the trackability of the catheter.
There remains a need for innovative securement devices for securing stents and similar medical devices.
All US patents and applications all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
The invention in various of its embodiments is summarized below. Additional details of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.
In one embodiment, the invention is directed to a medical device delivery system comprising an inner tube having a proximal end and a distal end. At least one securement hub is disposed about the distal end of the inner tube. The securement hub comprises an inner layer of material and an outer layer of material. The inner layer is made of a material more rigid than the outerlayer. A balloon is disposed about the securement hub and distal end of the inner tube. The balloon is supplied with inflation fluid via an inflation lumen in fluid communication with the balloon. The medical device delivery system may be used for delivering stents by disposing a stent about the balloon. Desirably, the medical device delivery system comprises two or more such securement hubs. Also desirably, the inner layer of the securement hub will be made of a metal and the outer layer will be made of a polymeric material.
In another embodiment, the invention is directed to a medical device delivery system comprising an inner tube with a marker band disposed about the distal end of the inner tube and a securement hub disposed about the marker band. A balloon is disposed about the securement hub and distal end of the inner tube and an inflation lumen is in fluid communication with the balloon. Desirably, the marker band is made from a radiopaque metal. The medical device delivery system may comprise one or more marker bands and one or more securement hubs. Each securement hub is disposed about a marker band. The medical device delivery system may be used for delivering stents by disposing a stent about the balloon.
In another embodiment, the invention is directed to a medical device delivery system comprising an inner tube and a securement hub disposed about the distal end of the inner tube. The securement hub includes an outer layer of a polymeric material and an inner layer. The inner layer is more rigid than the inner tube. A balloon is disposed about the securement hub and the distal end of the inner tube and an inflation lumen is in fluid communication with the balloon.
In yet another embodiment, the invention is directed to a medical device delivery system comprising an inner tube having a proximal end and a distal end and a multilayer securement hub disposed about the distal end of the inner tube. The multilayer securement hub is composed of a plurality of layers of material including a first layer of a first material and a second layer of a second material. The second material differs from the first material. A balloon is disposed about the multilayer securement hub and distal end of the inner tube and an inflation lumen is in fluid communication with the balloon.
A detailed description of the invention in its various embodiments is provided below.